The goal is to develop gene therapies in neonates and/or infants and toddlers. The aims are 1. determine the safety and efficacy of AAV vector, gene therapy in cystic fibrosis(CF) patients; and 2. to develop CF gene therapy applied early in life to avoid the progressive destruction of the airways. The primary focus is on CF. Project I: "Adeno-associated virus vectors (AAV) for CF gene therapy" will address the issues of safety of gene therapy using AAV vectors. The aims will be to: assess the efficiency and distribution of vector DNA transfer and to determine if repeated applications will cause any immunologic reactions, alterations in pulmonary function, or spread in distant organs in monkeys. This will be followed by a phase I clinical trial in adult CF patients. Project II: "Neonatal gene therapy with AAV" investigates the consequences of early (fetal and neonatal) administration of AAV" investigates the consequences of early (fetal and neonatal) administration of AAV vectors. Aims are to determine whether more progenitor and/or dividing cells are present in the developing airway, which cells are targeted by the vector, the lasting effect of vector administration and the effects on airway development. CF Pilot Project I will evaluate the specificity of site specific integration of wild-type and recombinant AAV vectors. It is known that wild-type AAV virus integrates into chromosome 91. Finally, there will be an Expression/ Tissue Culture Core, a Vector Core, a Clinical Core and an Administration Core.